A mobile device may determine a location of the mobile device using various methods. For example, the mobile device may include a Global Positioning System (GPS) receiver to receive GPS signals from one or more GPS satellites, and to calculate the location of the mobile device based on the GPS signals.
In various occasions, the mobile device may not be able to receive the GPS signals, for example, when the GPS signals are weak, e.g., when the device is located at an indoor location, e.g., a building and the like. As a result, the mobile device may not be able to determine the location of the mobile device.
Some mobile devices may utilize an inertial navigation system to determine the location of the device, e.g., when the device is not able to receive the GPS signals, or to accurately determine the location of the device based on the GPS signals.
The inertial navigation system may include one or more inertial navigation sensors configured to provide position, velocity and/or acceleration parameters. For example, a shown in FIG. 6, an inertial navigation system 600 may include one or more movement sensors, e.g., an accelerometer sensor 602 and the like, to detect a movement of the mobile device and to provide movement parameters corresponding to the movement of the mobile device, e.g., velocity and/or acceleration; and/or one or more orientation sensors, e.g., a gyroscope sensor 604, a magnetometer 606, and the like, to provide orientation parameters relating to the orientation of the mobile device. Inertial navigation system 600 may include a coordinate frame transformation 610 to transform a sensor body coordinate frame 612 into navigation coordinate frame 614.
The mobile device may determine the location of the device based on the parameters provided by the inertial navigation sensors. For example, the device may calculate a distance and a direction from a previous known location of the device based on the movement parameters and/or the orientation parameters.
The gyroscope 604 may have errors, e.g., mechanical errors, calibration errors, and the like, which may affect the accuracy of one or more of the orientation parameters. The gyroscope errors may decrease an accuracy of the determined location of the mobile device.